Baltimore (CNN)The Baltimore police investigation into the death of Freddie Gray doesn't support some of the charges, including the most serious, filed by the Baltimore City State's Attorney, potentially allowing lawyers representing the police officers the opportunity to undercut the prosecution, according to officials briefed on the separate probes conducted by the State's Attorney and police.

Already, defense attorneys are filing motions seeking to exploit differences between the separate state attorney and police investigations.

Lawyers for two officers have challenged a key finding of State's Attorney Marilyn Mosby's case: that a knife found on Freddie Gray was legal in Maryland and therefore the officers didn't have a right to arrest Gray. The police investigation found that the knife is illegal under Baltimore city code.

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Officials familiar with the probes also say the homicide investigation run by police investigators at most contemplated a manslaughter charge, not second degree murder as Mosby charged one of the officers, Caesar Goodson. To win conviction for murder, prosecutors must prove intent to kill. Manslaughter relates to unintentional killings.

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In addition, homicide investigators who were briefed by the medical examiner's office believed the examiner's autopsy report would likely find the cause of death to fall short of homicide, according to one official familiar with the case.

Instead, Mosby said that the medical examiner concluded that Gray's death was a homicide and that Gray's fatal injury to the head occurred in a police transport van that was taking him to the police precinct.

According to an official with Maryland's office of the chief medical examiner, where Gray's autopsy was performed, information was shared with police investigators throughout the process, a common practice. But the official said there is only one conclusion on manner of death and that was contained in the final autopsy report delivered to Mosby on the same day she announced her decision to bring charges.

Another issue could arise from the team Mosby relied on to lead her case: one of her top investigators, Avon Mackel, is a former high-ranking Baltimore police officer who was stripped of his command post in 2009 for failing to follow through on a robbery investigation that two of his officers mishandled and did not report. A Baltimore Sun report said police in the district were accused of classifying serious crimes as lesser in order to log lower crime rates.

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In October 2009, four months after his demotion, Baltimore County police sent a SWAT team to Mackel's home, responding a drunken incident in which he was seen holding a gun, according to a police report of the incident obtained by CNN.

Officers said an intoxicated Mackel refused to cooperate and was visibly upset, according to the report provided in response to a public records request. An officer then "observed the barrel of Mackel's handgun hanging over the edge of the molding at the top of the steps and saw Mackel pull the gun out of sight," the report said.

Police used a Taser on Mackel while he was on the phone with his father "crying and yelling," before he barricaded himself in his bedroom. The report doesn't say how the incident ended, but police said there was no arrest. A spokesman for the Baltimore County Police Department said "the [SWAT] tactical unit did assist with this incident, which ended peacefully."

Mackel didn't respond to calls and emails seeking comment. No one answered at his home.

Defense attorneys working on the case are already digging for ways to attack weaknesses in Mosby's case, according to defenders of the officers. Mackel's past, and whether he holds it against the police department, could present opportunities for the defense.

That has lead to concerns among some city officials that if Mosby's case fails to hold up, community reaction could explode again.

"If this case falls apart, then does Baltimore burn?" one official said.

Mosby took pains to distance herself from the police with her separate probe, including using her own investigators and not relying on the 40-plus member police task force set up to look in the death of Freddie Gray.

Photos:Cleaning up after Baltimore riots

Photos:Cleaning up after Baltimore riots

People help clean up a CVS pharmacy in Baltimore on Tuesday, April 28, the morning after riots broke out during protests on Monday, April 27. The unrest followed the funeral for Freddie Gray, who died of a severe spinal cord injury he got while in police custody. There were more than 230 arrests, 144 vehicle fires and 15 structure fires, a city official said.

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Photos:Cleaning up after Baltimore riots

Members of the community clean up debris on April 28 from the CVS that was burned and looted in the riots.

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Photos:Cleaning up after Baltimore riots

A neighborhood cleanup crew works to clear trash from the streets on April 28.

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Photos:Cleaning up after Baltimore riots

Caroline Byrd helps with cleanup efforts on April 28.

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Photos:Cleaning up after Baltimore riots

Volunteers help clear trash from a looted business on April 28.

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Photos:Cleaning up after Baltimore riots

A man sweeps the street as law enforcement officers stand guard on April 28.

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Photos:Cleaning up after Baltimore riots

Baltimore firefighters inspect a burned store on April 28.

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Photos:Cleaning up after Baltimore riots

People helping clean debris are seen in the reflection of a broken window on April 28.

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Photos:Cleaning up after Baltimore riots

Jason Park, left, and business owner Sung Kang survey the damage to his store on April 28.

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Photos:Cleaning up after Baltimore riots

Men wearing work gloves help clear debris on April 28.

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Photos:Cleaning up after Baltimore riots

Kailah Johnson, 5, joins her mother in a neighborhood cleanup on April 28. Schools were closed across the city.

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Photos:Cleaning up after Baltimore riots

Volunteers help clear the wreckage from damaged stores on April 28.

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Photos:Cleaning up after Baltimore riots

Employee Sam Wirtz, left, surveys the damage to his store that came during the unrest on Monday, April 27.

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But that separation could cut both ways.

The police findings -- including those that contradict some of Mosby's investigation -- will now be part of the evidence provided to defense attorneys.

The Baltimore police department has declined to comment on the investigation since it is now in Mosby's hands.

A spokeswoman provided a statement on behalf of Mosby defending the charges.

"While the evidence we have obtained through our independent investigation does substantiate the elements of the charges filed, I refuse to litigate this case through the media," she said in the statement. "The evidence we have collected cannot ethically be disclosed, relayed or released to the public before trial. As I've previously indicated, I strongly condemn anyone in law enforcement with access to trial evidence, who has or continues to leak information prior to the resolution of this case. These unethical disclosures are only damaging our ability to conduct a fair and impartial process for all parties involved."

Mosby has good reason to separate her probe from the police.

There is widespread community distrust of the police. And many critics say letting police departments investigate themselves is partly why alleged excessive use of force incidents by officers rarely draw serious punishment.

Police Commissioner Anthony Batts told CNN in an exclusive interview on Tuesday that Mosby called him about 10 minutes before she told the world about the charges.

However, Batts had an inkling that Mosby was preparing for a surprise move, according to people familiar with the matter, which is why he turned over his department's findings a day ahead of the deadline he had set.

Six Baltimore police officers were charged in the April 2015 death of Freddie Gray, who died of a severe spinal-cord injury while in police custody. But there were no convictions in the case. Three of the officers were acquitted before prosecutors dropped the charges against the remaining three in July 2016. Seen here is Lt. Brian Rice, who was part of the bike patrol that arrested Gray. On July 18, 2016, Rice was found not guilty of involuntary manslaughter, reckless endangerment and misconduct in office in connection with Gray's arrest and death.

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Photos:Baltimore officers in Freddie Gray case

Officer Caesar Goodson drove the van in which Gray was fatally injured. On June 23, Goodson was found not guilty on all charges, including the most serious count of second-degree depraved-heart murder.

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Photos:Baltimore officers in Freddie Gray case

William Porter was the first of the six officers to face a trial. It ended in a mistrial in December, and he had been scheduled to be retried before prosecutors dropped the charges against him. Porter was summoned by the van's driver to check on Gray during stops on the way to a police station. Prosecutors said Porter should have called a medic for Gray sooner than one was eventually called, and they said he also should have ensured that Gray was wearing a seat belt. Porter had been charged with involuntary manslaughter, second-degree assault, reckless endangerment and misconduct in office.

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Photos:Baltimore officers in Freddie Gray case

Edward Nero, one of three bike officers involved in the initial police encounter with Gray, was found not guilty of all charges in May. He was accused of second-degree intentional assault, two counts of misconduct in office and reckless endangerment.

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Photos:Baltimore officers in Freddie Gray case

Garrett Miller was another one of the bike officers involved in Gray's arrest. He placed Gray in a restraining technique known as a "leg lace" before Gray was placed in the van, said Marilyn Mosby, the state's attorney for Baltimore. All charges were dropped against Miller, who had been indicted on charges of second-degree intentional assault, two counts of misconduct in office and reckless endangerment.

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Photos:Baltimore officers in Freddie Gray case

Sgt. Alicia White was present during one of the stops to check on Gray's condition. She and two other officers saw Gray unresponsive on the floor of the van, and when White spoke to Gray and he did not respond, she allegedly did nothing to help him, prosecutors said. All charges were dropped against White, who had been indicted on charges of involuntary manslaughter, second-degree negligent assault, misconduct in office and reckless endangerment.